This present invention relates to a system and method for providing communication services over a network. More specifically, it relates to a Virtual Private Network using Voice over Internet Protocol signaling.
Virtual Private Networking is a widely deployed generic business service offering which provides customers with a closed user group environment across a plurality of physical locations. There are several subsets of Virtual Private Networking, one of the better known being Wide Area Centrex (WAC). Wide Area Centrex is generally deployed within a single local rate center and the switches are located in central offices. Virtual Private Networking is not affected by these constraints and its switches can be located in central offices or customer premises anywhere in the world, making it the closed user group superset.
The primary goal of Virtual Private Networking is to achieve a uniform private numbering plan that can be administered by the user. This goal is difficult to achieve between switches today due to telephone number assignment constraints and the limited capability of the current Signaling System 7. One current strategy involves assigning a particular customer to a single switch and using remote peripheral equipment to serve the various remote locations. This has obvious cost disadvantages in terms of underutilized facilities and non-standard administration requirements.
Traditional Voice over Internet Protocol solutions are based on translation of a Public Switched Telephone Network (PSTN) telephone number, such as, a Directory Number, into a physical Internet address associated with an endpoint or other termination. In this traditional concept, roaming is achieved by substituting various Internet addresses into the translation process to accommodate a user""s change of physical location. Private numbering plans always feature an abbreviated form of dialing. This tends to be some subset of the least significant digits in the Directory Number, generally the last four.
Because Directory Numbers are assigned by the Local Exchange Carriers (LECs) or by a third party number administrator, they are not optimized to facilitate private numbering plans. Increasingly, they simply reflect the random availability of Directory Numbers in an ever-shrinking pool of available numbers. These numbers are not contiguous, and are dictated by the geographic location of the serving network""s switches within the North American Numbering Plan (NANP).
Despite the above shortcomings, Directory Numbers continue to be used by the Public Switched Telephone Network world for Direct Inward Dialing (DID) towards Centrex extensions. Centrex service is a business offering which provides customers with features that are normally associated with Private Branch Exchanges. The services offered by Centrex capable central offices are shared with other business customers as well as with the Public Switched Telephone Network, thus offering a cost effective solution to provide switching and value added services. However, the use of Directory Numbers precludes a user""s ability to retain a service profile while moving amongst corporate locations, either in the short or long term. A different location dictates a different private number because a different Directory Number is needed to support Direct Inward Dialing. One solution is to move completely away from numbers and introduce user names. But this introduces other limitations.
It should be noted that numerical digits are still needed in the User address for two reasons: 1) it is more convenient to type in four digits of a remembered number than all the characters in a long alphabetical name; and 2) traditional telephone sets with conventional key pads have to be supported for the foreseeable future in most customer environments. Alphabetical names in Universal Resource Locator format can be made available for users who can take advantage of them.
What is needed is a Virtual Private Network supported by a plurality of switches, located either in central offices or in customer premises to function as if the customers were served by a single switch.
The system and method of the present invention includes an addressing scheme to support two layers of numbers, a first layer of numbers that identify individual users and a second layer that identifies Directory Numbers. The user numbers are assigned by the customer""s telephone system administrator, and remain with the users wherever they are located in the corporate network. They are artificial telephone numbers having no relationship whatsoever with the Directory Number, although in a preferred embodiment they consist of four digits and are set equal to the last four digits of the Directory Number. This is a default value, readily changed to another value by the system administrator should a numbering conflict arise. The only restriction on number assignment by the customer is that escape prefix digits such as xe2x80x9c9xe2x80x9d must be avoided. In a preferred embodiment, the Directory Number is the Network Address (NA). The artificial numbers assigned to specific users are the Customer Addresses (CA).
In a particular embodiment, the Virtual Private Network system includes a gateway in communication with both a Public Switched Telephone Network and users of the private network; a call agent in communication with the gateway for processing different requests received at the gateway and generating Network Addresses from user names; and a server-based interface including a Directory Server if needed for translating between a Network Address corresponding to a user name and a Customer Address and a Domain Name Server for translating the Network Address or Internet name to an Internet Protocol address which may then be sent to the gateway with setup instructions.
The foregoing and other features and advantages of the Virtual Private Network system and method using Voice over Internet Protocol will be apparent from the following more particular description of preferred embodiments of the system and method as illustrated in the accompanying drawings.